1. Field of Invention
This invention is an improved device for use in the manual sharpening of arrow broadheads, razor blades, and specialty blades.
2. Discussion of Prior Art
The need to sharpen or re-sharpen blades of cutting instruments is ancient. While in theory, the actions involved in the process of sharpening are fairly simple, in practice a good deal of skill is required, and sharpening has been a difficult task for the average person. This is particularly true of smaller blades. This is evidenced by the countless devices that have been designed to aid the user in the process of sharpening, and by the fact that entire industries exist solely to manufacture disposable blades of widely varying style and purpose.
The vast array of prior art devices for aiding in the manual sharpening of blades generally have had a common goal, which is to maintain a fixed angle between an abrasive sharpening surface and a blade as the blade is moved across the sharpening surface, or more recently, as the abrasive surface is moved across the blade. While this aspect of the sharpening process is critical, to efficiently sharpen any blade requires that several actions take place in concert:                1) The blade to be sharpened must move smoothly across an abrasive surface while being held at a fixed angle to the surface.        2) The entire length of the blade edge must come in contact with the abrasive surface at a uniform rate each time the blade is moved across the surface.        3) The blade must be turned over after each completed “pass” across the abrasive surface and a similar pass must be made on the opposite side of the blade.                    Step 3 is necessary to insure that a uniform bevel is maintained and because the action of moving the dull blade across the abrasive surface, such as a whetstone has two separate effects on the blade:            a) The portion of the blade edge that is in contact with the abrasive surface or the “underside” is ground away. Defects and deformities are removed and a clean smooth surface is created.            b) As the underside of the blade edge is ground away, microscopic burrs and filings are formed on the opposite or “top” side of the edge.            These burrs and filings are detrimental to the desired effect of sharpening and continue to build up with each pass across the abrasive surface. In order to minimize this undesirable effect, the blade must be turned over after each completed pass across the abrasive surface and a similar pass must be made on the opposite side. This process is repeated until the blade is sharp. Thus both sides of the blade edge bevel are uniformly ground, burrs and filings are not permitted to build up, and a greater degree of sharpness is achieved.                        
Devices that hold blades at fixed angles to a sharpening surface are well known in prior art and are known to consist of basically familiar, expected and obvious structural configurations. However, there has been a long-standing need for a device that will securely hold the blade to be sharpened at a fixed angle to the sharpening surface and:                1) ensure that the entire length of the blade edge is uniformly ground on each pass across the sharpening surface, and        2) easily facilitate the superior process of alternately passing each side of the blade across the sharpening surface.        3) enable the user to service both sides of the blades edge with a single blade clamping operation        
For example, U.S. Pat. No. 3,819,170 Longbrake shows a hand-held device for the sharpening of knives and arrow broadheads consisting of a vise for securing the blade to be sharpened, two individual guide bars mounted at the rear top and bottom of the vise, with each guide bar having a series of holes indicating several angle options, through which a length of rod with a sharpening stone attached to one end is passed, and the stone then is passed across the blade. This device secures the blade at a fixed angle to the sharpening stone but discourages the user from employing the process of alternately passing the stone over each side of the blade's edge, as the rod/stone must be withdrawn from one guide bar, the entire device inverted and the rod/stone reinserted in the corresponding angle hole of the opposite guide bar with each pass of the stone.
U.S. Pat. No. 5,431,068 Alsch depicts a device wherein a blade vise is horizontally mounted midway along a vertical main shaft which is topped with an assembly through which a single rod with multiple sharpening stones of varying grit mounted on one end is semi-permanently attached. Again, this devise does maintain a fixed angle between the blade and the sharpening surface but, the drawback of this system is that the blade must be unclamped, removed, turned over and re-clamped to sharpen the opposite side. This makes the process of sharpening more difficult and time-consuming than necessary. Further, passing the stone alternately over each side of the blade is impractical.
U.S. Pat. No. 3,654,823 Juranitch discloses a device for the sharpening of arrowheads consisting of a two-piece clamp, which grips the arrowhead, and through its shape, also maintains a fixed angle to a sharpening surface, such as a whetstone. Achieving uniform blade-to-stone contact on both sides of the blade is difficult because the blade must be precisely positioned in the clamp, and any misalignment or structural anomaly of the clamp will result in a portion of the blade edge being held above the surface of the whetstone. Additionally, the clamp body rides the surface of the stone, which wears the device itself and clogs the porous surface of the sharpening stone with additional metal filings.